Indeed. The self-congratulatory narrative around "EU funds" is obnoxious and ignorant. As you say, Poland's economic growth was similar before it had joined the EU. (Many economists then thought Poland's accession in 2004 was premature and should have been postponed.) Causes were cultural (there is a strong, traditional entrepreneurial streak in Polish culture) and related to the economic reforms undertaken during the transition from the centrally-planned economy of the socialist period. People need to remember that Poles did not choose the communist regime after the War. It was thuggishly and violently imposed onto Poland by the occupying Soviets. Poles merely endured a provisional acceptance of the regime, because they had no choice.

Furthermore, as the GP hints, EU funds earmarked for Poland don't necessarily remain in Poland as investment. Much of that money circulates back into the pockets of contributing countries. You have to look at the entire paper trail to understand where money is actually ending up.

Also worth noting: Poland didn't receive a dime of reparations after the War. Germany (and with later contribution by the Soviets) had unleashed such mind-boggling destruction on Polish cities, towns, cultural inheritance, industry, etc. that only the so-called Swedish Deluge matches or exceeds this devastation.

The EU presents certain clear economic benefits for member countries. Nobody disputes that. But the patronizing and paternalistic narrative of some countries - reminiscent of their goofy rationalizations for their occupation of that region during the 19th century - need to go away.